1. Field of the Invention
This invention relates to a memory device with a function to perform an operation and a method of performing an operation and storage.
2. Description of Prior Art
A functional memory is known as a device for storing image data or the like. A functional memory has not only a function to store data but also a function to perform a simple operation on the data stored in it. Namely, an operation can be performed in the functional memory and the result of the operation can be written back in its memory cell. A functional memory is advantageous because it can process a large amount of image data without imposing a load on an external main processor.
A functional memory provided with a ferroelectric capacitor is known (see FIG. 1 in JP-A-Hei 11-39883, for example). With a functional memory of this type, the number of transistors and wirings to be used can be reduced. Also, since a large amount of data being processed are not lost even when a trouble occurs in its power source or the like, the processing can be resumed immediately after the power source is recovered.
The conventional functional memory, however, has the following problem. As shown in FIG. 1 of JP-A-Hei 11-39883, a pair of memory cells are necessary to store a pair of data sets to be operated on. Thus, to process a large amount of data such as image data, a large number of memory cells are required. There is therefore a limit of the reduction in the size and production cost of the device.